"They will be brought to New York City in a courthouse just blocks from where the twin towers once stood," said Holder, who added that he will direct prosecutors to seek the death penalty for the men. "These were extraordinary crimes, and so we will seek maximum penalties."

Holder said of the attacks on 9/11 and the USS Cole, "Nearly 3,000 people lost their lives in those attacks. And in the years since, our nation has had no higher priority than bringing those who planned and plotted the attacks to justice."

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The detainees could be transferred from Guantanamo Bay within 45 days, once Congress is formally notified, which is expected to be today.

President Barack Obama today addressed the prosecution at a joint news conference in Tokyo with Japanese Prime Minister Yukio Hatoyama.

"This is a prosecutorial decision as well as a national security decision," the president said. "Here's the thing that I will say: I'm absolutely convinced that Khalid Sheik Mohammed will be subject to the most exacting demands of justice. The American people insist on it. My administration will insist on it."

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One line of thinking is that trying the suspected terrorists in federal court -- rather than using military commissions -- would send a powerful message to the international community and undo some of the damage the Guantanamo Bay detention camp has done to the U.S. image abroad.

The primary message would be that the United States can use its traditional federal court to try, convict and execute the people who devised the deadliest terrorist attack ever on U.S. soil. New York was the "sentimental favorite," one source told ABC News.

Putting these "ultra high-threat detainees," as the source called them, on trial in a major urban area, especially New York City, is likely to grab international headlines.

The FBI deployed a special team of agents to pull together evidence against the suspects, making sure it contained no information gained from controversial interrogation tactics, ABC News has learned.

After the fate of these individuals is determined, the government will move to lay out its plans for the Guantanamo Bay detention camp, although the president's deadline to shut down the facility by January will almost certainly not be met.

Khalid Sheikh Mohammed and Four Others to be Tried in New York

The American Civil Liberties Union, which has represented the men, praised the decision to charge them in federal court instead of continuing to use the military commissions that were initially launched during the Bush administration.

"The transfer of cases to federal court is a huge victory for restoring due process and the rule of law, as well as repairing America's international standing, an essential part of ensuring our national security, " ACLU director Anthony D. Romero said.

The five men include Mohammed, as well as Walid Muhammad Salih Mubarek Bin 'Attash, Ramzi Binalshibh, Ali Abdul Aziz Ali and Mustafa Ahmed Adam al Hawsawi.

Even before the news that the Obama administration will try some of the Guantanamo Bay detainees in U.S. federal courts, opponents of the plan were ratcheting up their criticism.

Critics say that bringing the men onto U.S. soil will create hazards for Americans, a concern that Obama has dismissed.

"I'm a prosecutor myself," said Holder. "The reality is based on all of my experience...that I am quite confident that the outcome in these cases will be successful."

But Holder's reassurance likely won't silence his critics.

House Minority Leader John Boehner, R-Ohio, called the decision irresponsible, saying in a statement, "The possibility that Khalid Sheik Mohammed and his co-conspirators could be found 'not guilty' due to some legal technicality just blocks from Ground Zero should give every American pause."

Michael Mukasey, former attorney general for the Bush administration, says that the men who plotted 9/11 weren't deterred by the prospect of being tried in federal courts.

"At least those moving this process forward," Mukasey wrote in a recent article in the Washington Post, "should consider whether the main purpose here is to protect the citizens of this country or to showcase the country's criminal justice system, which has been done before and which failed to impress Khalid Sheik Mohammed."

Sens. Sen. Lindsey Graham, R-S.C., John McCain, R-Ariz., Joe Lieberman, the Connecticut independent, and Jim Webb, D-Va., failed last week to push through an amendment that would have prohibited the prosecution of any individual suspected of involvement with the 9/11 attacks from being tried in Article III, or federal, courts.

On his first day of office, Obama signed an executive order to close the detention camp at some point. Although the original deadline for closure was January 2010, administration officials have said that it could take longer.

No Word on Plans for Other Guantanamo Detainees

In May, the president said that some detainees would go to federal court, and that others would be tried in military commissions revamped by congressional legislation. Today, Holder announced that five cases, including that of Abd al Rahim al Nashiri, accused of plotting the 2000 attack on the USS Cole which killed 17 U.S. sailors, would be held in revamped military commissions.

In theory, military commissions have less stringent procedural standards for evidence that may have been obtained in the heat of war. Military commissions have also been preferred as a more secure method to protect sources and methods of intelligence gathering.

But officials have not yet said what the administration plans to do with the nearly 210 other men being held.

The administration has found three countries willing to take 25 detainees whom it no longer considers a threat, and hopes to transfer many more out of the country.

A looming question, however, is what to do with detainees who will not be charged but are too dangerous to release.

Congress recently passed legislation allowing the administration to bring onto U.S. soil those men that it plans to charge but the legislation only dealt with those who were being criminally prosecuted.